In the course of a screening program to find new and active compounds from soil microorganisms, we isolated two cultures of Streptomyces sp. (isolates 124 and 275). Both of these cultures produce an active antibiotic substance which showed a strong inhibitory activity in vitro against four pathogenic strains of Treponema hyodysenteriae, the causative agent of swine dysentery. It also showed useful activity against other microorganisms that cause infectious diseases in both humans and animals. This disclosure describes the characteristics of the antibiotic-producing organism and the isolation, purification, and characterization of the antibiotic produced by it.
Both soil isolates of Streptomyces sp. that produce Treponemycin were identified as S. albovinaceous. It has been reported that the same species of Streptomyces also produces another antibiotic (Nancimycin), which is active against gram-positive bacteria and certain viruses (R. Sonvick, J. F. Pagano, B. Brook, and J. Vandeputte, U.S. Pat. No. 2,999,048, 1961). The chemical and other properties of Nancimycin seem to be distinct from those of Treponemycin. For example, the three UV absorption bands of Nancimycin (at 225, 305, and 425 nm) are absent in the UV spectra of Treponemycin. Unlike Treponemycin, the antibiotic Nancimycin is a non-nitrogenous compound with a molecular formula of C.sub.23 H.sub.30 O.sub.10 (Treponemycin, C.sub.28 H.sub.43 O.sub.6 N). In addition to these differences, the characteristic IR absorption band at 2,210 nm for the nitrile function of Treponemycin is absent in the IR spectra of Nancimycin. These characteristics demonstrate that Nancimycin and Treponemycin, although produced by the same species of Streptomyces, are actually two different and distinct compounds. The production of structurally different antimicrobial compounds by common species of Streptomyces is not an uncommon phenomenon, since there are abundant instances in the literature in which the same species of Streptomyces is known to produce more than one group of antibiotics (1,16).